Turbo fan

ABSTRACT

A turbo fan comprises: a hub coupled to a rotational shaft of a driving device; a plurality of blades installed on an outer circumference of the hub in a radial direction; and a shroud connected to the plurality of blades on opposite side of the hub centering around the blades; wherein a leading edge of the blade comprises: a connection part which is connected to the shroud; an extension part which is extended as a straight line parallelly with the rotational shaft from the hub; and a curved surface part which is formed as a convex curved surface between the extension part and the connection part.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a turbo fan, and particularly, to a blade structure for the turbo fan.

[0003] 2. Description of the Background Art

[0004] Generally, a fan is used for sending air by rotation force of a rotor, and used in a refrigerator, an air conditioner, and a cleaner.

[0005] Especially, the fan can be divided into an axial fan, a sirocco fan, and a turbo fan according to methods for sucking and discharging the air or shape of the fan.

[0006] The turbo fan sucks the air from an axial direction of the fan, and discharges the air through a side surface part of the fan in radial direction. The turbo fan does not include a duct because the air is naturally sucked into the fan and discharged to outside, and is applied to relatively large size goods such as ceiling air conditioner.

[0007]FIG. 1 is a plan view showing a conventional turbo fan, and FIG. 2 is a longitudinal cross-sectional view showing the conventional turbo fan.

[0008] As shown in FIGS. 1 and 2, the conventional turbo fan comprises: a shroud 4; a hub 2 to which a driving device (not shown) is coupled; and a plurality of blades 3 formed on an outer circumference of the hub 2 in a radial direction and having one side connected to the shroud 4.

[0009] According to the structure described above, the turbo fan 1 includes a suction part 7 for sucking the air on an upper part thereof, a plurality of flow paths 6 for guiding the air which is sucked through the suction part 7, and a plurality of discharge parts 8 for discharging the sucked air on side surface part of the turbo fan 1.

[0010] Operations of the conventional turbo fan having the above structure will be described as follows. When the turbo fan 1 is rotated by the driving device (not shown), the air is sucked into the suction part 7 by the rotation of the blades 3, and the air which is sucked through the suction part 7 is discharged to the discharge parts 8 via the flow paths 7.

[0011] Meanwhile, in the conventional turbo fan, a leading edge on a center part between an end part on hub side and an end part on the shroud side is formed as a straight line as shown in FIG. 2, and a curved part or a bent part may be formed on the hub side in order to get a needed area for the blades.

[0012] However, the shape of the blades 3 in the conventional turbo fan is not suitable for “L” shaped air flow, that is, the air is sucked from the suction part 7 and discharged to the discharge part 8, and therefore a noise may be generated by unstable air flowing such as vortex flow and an efficiency of the turbo fan is reduced.

SUMMARY OF THE INVENTION

[0013] Therefore, an object of the present invention is to provide a turbo fan including a blade having a shape which is able to reduce noise and increase efficiency by preventing unstable air flowing such as vortex flow in “L” shape of air flow in the turbo fan.

[0014] To achieve the object of the present invention, as embodied and broadly described herein, there is provided a turbo fan comprising: a hub coupled to a rotational shaft of a driving device; a plurality of blades installed on an outer circumference in a radial direction; and a shroud on the plurality of blades of opposite side of the hub centering around the blades, and a leading edge of the blade comprising: a connection part which is connected to the shroud; an extension part which is extended parallelly to the rotational shaft from the hub; and a curved part formed as convex curved surface between the extension part and the connection part.

[0015] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

[0017] In the drawings:

[0018]FIG. 1 is a plan view showing a conventional turbo fan;

[0019]FIG. 2 is a longitudinal cross sectional view showing the conventional turbo fan;

[0020]FIG. 3 is a longitudinal cross sectional view showing a turbo fan according to the present invention;

[0021]FIG. 4 is an enlarged cross sectional view showing principal parts in FIG. 3;

[0022]FIGS. 5A, 5B, and 5C are longitudinal cross sectional views showing a turbo fan in which a leading edge of a blade is formed as a straight line, the conventional turbo fan, and the turbo fan according to the present invention respectively; and

[0023]FIGS. 6A, 6B, and 6C are graphs showing air flow and noise generation on respective parts of the turbo fans in FIGS. 5A, 5B, and 5C when flow rate is 18.5 m³/min.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[0025]FIG. 3 is a longitudinal cross-sectional view showing a turbo fan according to the present invention, and FIG. 4 is an enlarged cross sectional view showing principal parts of the turbo fan in FIG. 3.

[0026] As shown in FIG. 3, the turbo fan 10 according to the present invention comprises: a hub 12 which is coupled to a rotational shaft 19 of a driving device (not shown); a plurality of blades 13 which are formed on an outer circumferential surface 12 a of the hub 12 in a radial direction; and a shroud 14 connected to the plurality of blades 13 on opposite side of the hub 12 centering around the blades 13.

[0027] A leading edge of the blade 13 comprises: a connection part 13 a which is connected to the shroud 14, an extension part 13 c which is extended parallelly with the rotational shaft 19 from the outer circumferential surface 12 a of the hub 12, and a curved surface part 13 b which is formed as a convex curved surface between the extension part 13 c and the connection part 13 a. It is desirable that a length of the extension part 13 c of the blade is 40%˜60% of a distance D between the outer circumferential surface 12 a of the hub 12 and the connection part 13 a of the blade 13 and the hub 12.

[0028] According to the above structure, the turbo fan 10 includes a suction part 17 for sucking the air on an upper part, a plurality of flow paths 16 for guiding the air which is sucked through the suction part 17 at a center part of the turbo fan 10, and a plurality of discharge parts 18 for discharging the sucked air on a side part of the turbo fan 10.

[0029] Operations of the turbo fan according to the present invention will be described as follows.

[0030] When the turbo fan 10 is rotated by the driving device (not shown), the outer air is sucked into the suction part 17 by the rotation of the blades 13, and the air sucked through the suction part 17 is discharged to the discharge part 18 via the flow paths 16.

[0031]FIGS. 5A, 5B, and 5C are longitudinal cross sectional view showing a turbo fan in which the leading edge of the blade is formed as a straight line, the conventional turbo fan, and the turbo fan according to the present invention.

[0032]FIGS. 6A, 6B, and 6C are graphs showing air flows and noise generation on respective parts of the turbo fans in FIGS. 5A, 5B, and 5C when the flow rate is 18.5 m³/min.

[0033]FIGS. 5A, 5B, and 5C and FIGS. 6A, 6B, and 6C are experimental examples, and the blade 13 in the turbo fan 10 according to the present invention in FIG. 5C is formed vertically from the outer circumferential surface 12 a of the hub 12, and the extension part 13 c is formed as about 50% of the distance D from the outer circumferential surface 12 a of the hub 12 to a part where the blade 13 and the hub 12 are connected to each other.

[0034] As shown in FIGS. 6A, 6B, and 6C, when the flow rate of the turbo fan is 18.5 m³/min, the air flows on the respective parts of the turbo fan according to the present invention has less velocity standard deviation than that of the conventional turbo fan, and therefore the flowing speed of the air is distributed evenly and the noise generated when the turbo fan is operated is reduced.

[0035] That is, the turbo fan according to the present invention is able to increase the sending capacity of the turbo fan by enlarging the cross sectional area of the blade 13, and at the same time, is able to reduced the noise by reducing the vortex flow due to the “L” shape air flowing in the turbo fan and the unstable air flowing.

[0036] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims. 

What is claimed is:
 1. A turbo fan comprising: a hub coupled to a rotational shaft of a driving device; a plurality of blades installed on an outer circumference of the hub in a radial direction; and a shroud coupled to the plurality of blades on opposite side of the hub centering on the blades; wherein a leading edge of the blade comprises: a connection part which is connected to the shroud; an extension part which is extended as a straight line parallelly with the rotational shaft from the hub; and a curved surface part which is formed as a convex curved surface between the extension part and the connection part.
 2. The turbo fan of claim 1, wherein the extension part of the blade is formed to be about 40%˜60% of a distance from the outer circumferential surface of the hub to a part where the blade and the hub are connected to each other. 